I made the running model of a turboshaft engine which uses a radial compressor and a radial turbine by vacuum cleaner before. https://www.myminifactory.com/object/3d-print-turboshaft-engine-with-radial-compressor-and-turbine-75203

This is the purely cutaway model of it.A. The features are as follows. ① Radial compressor (Impeller), Diffuser ② Radial turbine rotor, Turbine nozzle ③ Planetary reduction gears ④ Output shaft ⑤ No metal bearing is used for every shafts.